Kenta Yoshida, Masaki Shimodaira, Takeshi Toyama, Yasuo Shimizu, Koji Inoue, Toshimasa Yoshiie, Kons 

To evaluate dislocations induced by neutron irradiation, we developed a weak-beamscanning transmission electron microscopy (WB-STEM) system by installing a novelbeam selector, an annular detector, a high-speed CCD camera and an imaging filter inthe camera chamber of a spherical aberration-corrected transmission electron microscope.The capabilities of the WB-STEM with respect to wide-view imaging, real-timediffraction monitoring and multi-contrast imaging are demonstrated using typicalreactor pressure vessel steel that had been used in an European nuclear reactor for30 years as a surveillance test piece with a fluence of 1.09 × 1020 neutronscm–2. The quantitativelymeasured size distribution (average loop size = 3.6 ± 2.1 nm), number density ofthe dislocation loops (3.6 × 1022m−3) and dislocation density (7.8 × 1013mm–3) werecarefully compared with the values obtained via conventional weak-beam transmission electronmicroscopy studies. In addition, cluster analysis using atom probe tomography (APT)further demonstrated the potential of the WB-STEM for correlative electron tomography/APT experiments.

Microscopy, 2017, 120–130
https://doi.org/10.1093/jmicro/dfw111

Keywords: STEM, diffraction contrast, weak-beam, irradiation damage, dislocation